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science

light microscope

enables us to see the overall shape and structure of a cell
passes visible light through a specimen
can study living cells, cell, tissues that have been stained
can only magnify about 1000 times

total magnification

a times b
ocular times objective

magnification

the increase in the apparent size of an object

resolution

a measure of the clarity of the image

electron microscope

uses a beam of electrons rather than light
greater resolution than LM and can magnify up to 100,000 times
cant be used with living specimens

small cell- surface areas

small cell has greater ratio of surface area to volume than a large cell of the same shape
surface area- cell membrane
volume- cytoplasm

cell increases in size..

its volume increases faster than its surface area
cells are more efficient when they are small

prokaryotic cells definiton

simpler than eukaryotic cells
have no nucleus
bacteria, archae

eukaryotic cells defintion

protists plants animals fungi
have a nucleus and other membrane bound organelles

all cells share common feautures

plasma membrane- makes proteins
DNA
ribosomes

prokaryotic cells

no real nucleus
DNA is coiled into a nucleoid region in the cytoplasm
cytoplasm includes ribosomes
plasma membrane
cell wall

eukaryotic cells

larger and partitioned into functional compartments called organelles
have a true nucleus

animal cells

no cell wall
contain centrioles and lysosomes
may have flagella
can have tiny vacuoles (bubble filled with water)

plant cells

have both plasma membrane and rigid cellulose cell wall
have large central vacuole and chloroplasts
lack centrioles, lysosomes, and flagella
have mitochondria( takes glucose converts it to atp)

nucleus

cells genetic control center and contains DNA
controls cellular activities
separated from the cytoplasm by the nuclear envelope

nuclear envelope

nuclear pores in the envelope control flow of materials in and out
ribosomes are synthesized in the nucleolus (dark circles inside nucleus)

endomembrane

many cell organelles connected through this
a series of membranous organelles

endoplasmic reticulum

continuous network of flattened sacs and tubes

smooth endoplasmic reticulum

lacks attached ribosomes
makes lipids
proccesses materials such as toxins and drugs in liver cells

rough endoplasmic reticulum

studded with ribosomes
manufactures membranes
modifies and packages proteins

golgi apparatus

a stack of flattened membranous sacs that finishes, sorts, ware houses, and ships cell products
UPS of cell

lysosomes

sacs of enzymes that form from the gogi apparatus
function in digestion within a cell
destroy bacteria that have been ingested into white blood cells
recycle damaged organelles
abnormal lysosomes can cause fatal diseases

vacuoles

function in the general maintenance of the cell (storing water)
plant cells contain large center vacuole
some protists have contractile vacuoles that pump excess water out of a cell

chloroplasts

convert solar energy to chemical energy
found in plants and are the sites of photosynthesis

photosynthesis

sunlight+water+CO2 to glucose and oxygen

mitochondria

harvest chemical energy from food
found in nearly all eukaryotic cells
carry out cellular respiration
convert the chemical energy in food to ATP for cellular work

cellular respiration

oxygen+glucose to CO2+H2O+36 ATP
ATP is adenosine triphosphate

cytoskeleton

network of three types of protein fibers that provides structure for the cell
1. microfilaments (thin)
2. intermediate filaments (medium)
3. microtubules (thickest)
cilia and flagella move when microtubules bend
move whole cells or materials across the cell surface

plant cell walls

made largely of cellulose (carb)
provide protection and support
connect by plasmodesmata- channels through the wall

animal cell membranes

embedded in an extracellular matrix that binds cells together in tissues
connected by cell junctions

membrane structure and function

plasma membrane forms a boundary between a living cell and its sorroundings
shows selective permeability only allowing certain things to enter and leave the cell

phospholipids

are the main structural components of membranes
1 polar phosphate group attached to hydrophilic glycerol head
2 nonpolar fatty acids, hydrophobic tails

phospholipids in membrane

form a bilayer that is selectively permeable

small nonpolar lipid

soluble molecules pass through- polar molecules not soluble in lipids and do not pass though

difusion

the movement of molecules from an area of high concentration to an area of low concentration

passive transport

across membranes occurs when a molecule diffuses down a concentration gradent (from high to low concentration)

small nonpolar molecules

such as O2 and CO2 diffuse easily across the phospholipid bilayer of a membrane

facilitated difusion

transport proteins help substances difuse down a concentration gradient (move from higher to lower concentration)

osmoregulation

the control of water balance

isotonic solution

solute concentration is the same in both solutions you are comparing

hypotonic solution

has more water and less solute than the solution you are comparing it to (dilute)

hypertonic solution

had more solute and less water than the solution you are comparing it to (concentrated)

animal cell what solution is best?

isotonic is best
water comes out of cell at the same rate it is coming in

plant cell what solution is best?

hypotonic solution causes cell to poof up making the plant stay upright

plasmolysis

where cell membrane pulls away from the cell wall causing plant to wilt

Active transport

requires energy to move solutes against a concentration gradient (from low to high concentration) allows to stock pile solutes for later on
requires ATP (source of energy) and transport proteins

exocytosis

a vesicle of large waste may fuse with the membrane and expel its contents outside the cell

endocytosis

extensions of the cytoplasm move out to sorround large materials the cell needs
1. pinocytosis- engulfing liquids
2.phagocytosis- engulfing solids

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